The proposed research is concerned with the initial stages of visual information processing. It is directed towards an understanding of how information is represented in and selectively encoded from iconic storage, and the interaction with and control of this process by backward masking with an effective pattern mask. More specifically the research will attempt to increase our understanding of how stimulus energy interacts with the duration of iconic storage, the manner in which spatial selective attention allows encoding of information from specific locations in iconic storage, and whether encoding proceeds as full identification directly off an iconic storage, or whether the information stored as an icon must or can, under certain conditions, be transferred to another storage system, e.g. a visual image, for the identification process. These questions are investigated in a series of experiments which include varying the energy, content, and configuration of brief visual displays, presenting simultaneous and delayed indicators, and obtaining backward masking functions with an effective pattern mask for both indicators and stimulus displays. This latter procedure presumably provides a direct measure of processing time from iconic storage. Comparisons of backward masking ranges, delayed indicator functions, recognition accuracy, and reaction times, allow inferences to be made concerning the locus and nature of the initial stages of visual information processing.